Nitric oxide synthase (NOS) in the trigeminal vascular system and other brain structures related to pain in rats

Nitric oxide (NO) is considered to be a key mediator in the pathophysiology of migraine but the localisation of NO synthesizing enzymes (NOS) throughout the pain pathways involved in migraine has not yet been fully investigated. We have used quantitative real-time PCR and Western blotting to measure the respective levels of mRNA and protein for nNOS and eNOS in peripheral and central tissues involved in migraine pain: dura mater, pial arteries, trigeminal ganglion (TG) trigeminal nucleus caudalis (TNC), periaqueductal grey (PAG), thalamus, hypothalamus, cortex, pituitary gland, hippocampus and cerebellum. iNOS was excluded from the present study because it was not induced. In the trigeminal vascular system we found the highest expression of nNOS mRNA in pial arteries. However, protein expression of nNOS was maximum in TNC. Among other brain structures, nNOS mRNA and protein expression was remarkably higher in the cerebellum than in any other tissues. Regarding eNOS in the trigeminovascular system, the highest mRNA expression was found in pial arteries. In the other brain structures, eNOS mRNA expression was similar but with lowest mRNA concentration in the pituitary gland and the highest concentration in cortex. The same pattern of expression was also observed with the eNOS protein. In conclusion, we found both nNOS and eNOS located to areas relevant to migraine supporting the involvement of NO in migraine mechanisms.     

Localization and functional significance of a polymorphic determinant in the third component of human complement

A polymorphic epitope in the third component of human complement was studied. This allotypic system is distinct from the electrophoretically determined C3 S/F polymorphism and is defined by the recognition of one allotype by a monoclonal antibody. Allotypic protein variants, C3F+ (reactive with this antibody) and C3S- (non-reactive with the antibody), were purified. Deglycosylation studies and N-terminal sequencing of CNBr fragments, reactive with the antibody, revealed that the polymorphic epitope was present in a beta chain fragment of mol. wt 20,000. In the intact C3 molecule, this fragment is situated with N-terminus at residue No. 202, using the numbering of the cDNA derived amino acid sequence of human prepro C3. Addition of Fab fragments from the alloselective antibody preferentially inhibited the activity of C3F+ in a haemolytic assay which is selective for the C3 activity in the alternative complement pathway.     

Electrostatic sheathing of lipoprotein lipase is essential for its movement across capillary endothelial cells

GPIHBP1, an endothelial cell (EC) protein, captures lipoprotein lipase (LPL) within the interstitial spaces (where it is secreted by myocytes and adipocytes) and transports it across ECs to its site of action in the capillary lumen. GPIHBP1’s 3-fingered LU domain is required for LPL binding, but the function of its acidic domain (AD) has remained unclear. We created mutant mice lacking the AD and found severe hypertriglyceridemia. As expected, the mutant GPIHBP1 retained the capacity to bind LPL. Unexpectedly, however, most of the GPIHBP1 and LPL in the mutant mice was located on the abluminal surface of ECs (explaining the hypertriglyceridemia). The GPIHBP1-bound LPL was trapped on the abluminal surface of ECs by electrostatic interactions between the large basic patch on the surface of LPL and negatively charged heparan sulfate proteoglycans (HSPGs) on the surface of ECs. GPIHBP1 trafficking across ECs in the mutant mice was normalized by disrupting LPL-HSPG electrostatic interactions with either heparin or an AD peptide. Thus, GPIHBP1’s AD plays a crucial function in plasma triglyceride metabolism; it sheathes LPL’s basic patch on the abluminal surface of ECs, thereby preventing LPL-HSPG interactions and freeing GPIHBP1-LPL complexes to move across ECs to the capillary lumen.     

Attenuated insulin action on glucose uptake and transport in muscle following resistance exercise in rats.

A previous study reported elevations of insulin-mediated muscle protein synthesis following four days of resistance exercise in rats (Fluckey et al. 1996. Am J Physiol 270, E313-E319). The purpose of this study was to determine if insulin-stimulated muscle glucose uptake (a-v diff.) and 2-deoxyglucose (2-DG) transport were altered under similar conditions. The protocol consisted of squat-like exercises during four sessions with progressively increased weight (70-190 g). Each session consisted of 50 repetitions and sessions were separated by 48 h. Sixteen hours after the last exercise session, basal glucose uptake in perfused hindlimbs was not different (P > 0.05) between exercised (n=6) and non-exercised controls (n=6). However, there was a significant (P < 0.05) attenuation of insulin-stimulated (20 000 microU mL-1) glucose uptake in exercised vs. non-exercised rats (491 +/- 31 vs. 664 +/- 58 micromol glucose-1 g-1 [15-min insulin period]-1, respectively). Following resistance exercise, insulin-stimulated 2-DG transport, measured during the last 10 min of the perfusion period, was significantly reduced (P < 0.05) in the soleus, white gastrocnemius and extensor digitorum longus muscles. Additionally, GLUT-4 glucose transporter protein content was significantly reduced (P < 0.05) in white gastrocnemius and extensor digitorum longus muscles. These results demonstrate that insulin-stimulated glucose uptake and transport are reduced after resistance exercise. Furthermore, the applied resistance exercise protocol causes directionally opposite changes of insulin action in two major metabolic pathways, i.e. glucose transport and protein synthesis.     

Screening and brief intervention targeting risky drinkers in Danish general practice--a pragmatic controlled trial

AIMS: Recommendations for routine alcohol screening and brief counselling intervention in primary health care rest on results from intervention efficacy studies. By conducting a pragmatic controlled trial (PCT), we aimed at evaluating the effectiveness of the WHO recommendations for screening and brief intervention (SBI) in general practice. METHODS: A randomized PCT (brief counselling intervention vs no intervention) involving 39 Danish general practitioners (GPs). Systematic screening of 6897 adults led to inclusion of 906 risky drinkers, and research follow-up on 537 of these after 12-14 months. Outcome measures focused on patients' acceptance of screening and intervention and their self-reported alcohol consumption. RESULTS: Patient acceptance of screening and intervention -10.3% (N = 794) of the target population (N = 7, 691) explicitly refused screening. All intervention group subjects (N = 442) were exposed to an instant brief counselling session while only 17.9% of them (79/442) attended a follow-up consultation that was offered by their GP. Consumption Changes At one-year follow-up, average weekly consumption had increased by 0.7 drinks in both comparison groups. As secondary findings, we observed an indiscriminate absolute risk reduction (ARR = 0.08 (95% CI: -0.02; 0.18)) in male binge drinking, but adverse intervention effects for women on the secondary outcomes (binge drinking ARR = -0.30 (95% CI: -0.47; -0.09)). CONCLUSIONS: The results of brief interventions in everyday general practice performed on the basis of systematic questionnaire screening may fall short of theoretical expectations. When applied to non-selected groups in everyday general practice SBI may have little effect and engender diverse outcome. Women may be more susceptible to defensive reactions than men.     

Knowledge in health technology assessment: who, what, how?

Health systems are placing more and more emphasis on designing and delivering services that are focused on the patient, and there is a growing interest in patient aspects of health policy research and health technology assessment (HTA). Only a few HTA agencies use and invest in scientific methods to generate knowledge and evidence about the patient aspects of a given technology. This raises questions about how knowledge is produced in HTA reports and what kind of knowledge is considered relevant. This article uses a Danish HTA on patient education from 2009 as empirical material for a critical examination and discussion of knowledge and knowledge production about the patient aspects of HTA.